In the prior art, methyl isobutyl ketone (MIBK) has been produced in a three-stage process, by aldol condensation of acetone to form diacetone alcohol which is catalyzed by a base, dehydration of that alcohol to mesityl oxide with an acid catalyst, and hydrogenation of that unsaturated ketone to MIBK with nickel or copper chromite catalyst (Kudo, S., "Formation of Higher Molecular Weight Ketones from Acetone or Isopropanol," J. Chem. Soc. Japan, Ind. Chem. Sect., 58 (1955), 785787; Showa Denkc, "Production of Methyl Isobutyl Ketone from Acetone," Japanese 46-2009 (Jan. 19, 1971); and Minoda, S., et al., "Acetone Purification," French 1,535).
MIBK has also been synthesized from hydrogen and acetone in one step under high pressure in the presence of a palladium-containing cation exchange resin catalyst. Disadvantages of this Pd-resin catalyst process are the short life of the catalyst, the problem of its regeneration due to the thermal instability of the resin (i.e. an organic polymer) at temperatures above 160.degree. C. and its tendency for inducing polymer formation, plus the high cost of the required high pressure system and its complicated operation ("New Solvent Process," Ind. Research (July 1968), 25-26; and Takagi, K., et al., "Methyl Isobutyl Ketone," German 1,936,203 (Feb. 12, 1970)).
Japan Kokkai 73/16492 describes a process in which MIBK was obtained in a yield of only 13.4% by vapor phase reaction of acetone with hydrogen at 250.degree. C. using a 0.01-2.00% Pd-containing 13X zeolite catalyst.
German Offen. 3,021,764 discloses a process for preparing MIBK with a 36% yield using a transition metal complex catalyst, but at a high pressure of 180 atm. It has the disadvantages of high pressure operation, and the difficulties of separating the products from the homogeneous catalyst.
U.S. Pat. No. 4,801,752, issued Jan. 31, 1989, of common assignee herewith, discloses a process for selective production of N-alkyl and N,N-dialkylaniline by reacting in vapor phase aniline with an alkanol having 1--3 carbon atoms, e.g. methanol, at 300.degree.-500.degree. C. and 1-5 atm. pressure, in the presence of a crystalline aluminosilicate catalyst having a silica to alumina ratio of 20-700:1, which may be modified with alkali metal, alkali earth metal or transition metal ions, such as a ZSM-5 zeolite containing sodium or hydrogen cations impregnated or ion-exchanged with cesium, magnesium, ferric or potassium ions (Chen, P. Y., et al., "The Selective Alkylation of Aniline With Methanol Over ZSM-5 Zeolite," Chem. Abst., July 6, 1987, vol. 107:6705h).